Pressure controlling appliance



July 15 1952 A. CARTER 2,603,477

PRESSURE coNTRoLLNG APPLIANCE Filed July 6, 1949 4 sheets-sheet 1 4 Sheets-Sheet 2 Filed July e, 1949 Inventor A. CARTER PRESSURE CONTROLLING AFPLIANCEl July 15, 1952 Filed July 6, 1949 m0 L. 0. Mgg VV V555/,WM ,n w y ,.7 .la 0 M2, ,NM @www3 JW///w/y #w Inventor r July l5, 1952 A. CARTER 2,603,477

PRESSURE CONTROLLING APPLIANCE:

F'iled July 6. 1949 4 Sheets-Sheet 4 T- ////A\ /9 m@ HomeyA Patented July 15, 1952 PRESSURE CONTROLLIG APPLIAN CE Arthur Carter, Halesowen, near Birmingham England Application July 6, 1949, Serial No. 103,273

In Great Britain July 8, 1948 6 Claims. (Cl. 267-1) resistance to a moving part.

The' said pressure controlling or cushioning appliances are of the kind in which a hydraulic fluid is acted upon by a main-ram or plunger in a primary cylinder and is forced through a resistance opening or passage into a secondary cylinder in order to act upon and depress a piston therein, said piston operating against a spring or other elastic medium which returns v'- the piston and displaced fluid when the applied 'L force is relieved from the ram or main plunger, and-a balancer pump, operated by a moving part of the appliance, being provided for automatically returning to the secondary cylinder a quantity 1 ofgfluid to compensate for leakage past the plung- 1 er and piston in the primary and secondary cylinders. f

In apparatus of the kind referred to, the pump has comprised a stationary member and a movable member operated by the piston in the secondary cylinder, the movable member having in itA a port or recess which comes to a position that will allow fluid to enter the pump cylinder only after the said piston has moved through a certainv distance, with the result that the pump will not charge effectively for small movements, and therefore, during'small vmovements of the main ram, leaking uid is not replaced and the said ram tends to. fall lower and lower in its cylinder. 1

f The object of the present invention is to provide aV pressure controlling or cushioning appliance,fof the kind referred to, having an improved form of pump which will ensure an effective pumping operation with either large or small movements of thermain ram and secondary piston.

According to the invention, a pressure controllingr or cushioning appliance, ofthe kind referred to, is provided with a balance pump, for replacing leakage fluid, comprising plunger and cylinder members, one of which is carried by the piston in the secondary cylinder, and vris characterised by the fact that inlet and outlet passages each controlled bya one-way valve are provided respectively for admitting fluid into the pump cylinder from a fluid-containing vessel and for discharging fluid from said'cylinder into a space above the piston in the secondary cylinder, and that va relief passage or sp'a'cefv is provided in the wall o1' the pump cylinder for cooperation with the pump plunger, the arrangement being such that pumping takesplace only While the piston in the secondary cylinder vis moving within an upper portion of its full range of stroke limited between the maximumF top position and a position at a predetermined distance below said top position, the relief passage or space in the pump cylinder wall being ineffective during this portion of the stroke but co-operating with the pump plunger to connect the working space of the pump cylinder to exhaust during movement of the secondary cylinder piston below said lower pumping-limit position.

- In one form of the invention the pump coming stopped when the said passage or space of the plunger is uncovered by the larger diameter'or relieved portion of the cylinder.

The pump may be submerged i'n fluid contained inl a feeder tank with which the primary and secondaryv cylinders communicate, said feeder tank being furnished with a hand-pump for charging fluid into the main cylinder.

'Figure 1 of the accompanying drawings is va sectional elevation of an appliance for controlling Vthe downward movement of the pressure or` draw ring of a press, in accordance with one form4 of the invention. v Y

FigureA 2 is asectional view, on a larger scale, of a portion of the pump, the plunger being shown in the same position as in Figure l.

Figure 3 is a similar view to Figure 2, but shows the plunger when depressed from its position# in Figures l and'2. Y

- Figure 4 is a vertical section through a hydraulic cushioning appliance in'accord'ance with a-nother form of the invention. y

Figure 5 is a section, on a larger scale, through a portion of the pump'employed in this modification, the plunger being shown in the same position as in Figure 4.'

Figure 6 is a similar view to Figure 5, but shows the plunger depressed below the position in Figures 4 and 5.

Figure 7 represents a section through an appliance having a modied form of pump.

Figure '7A shows a modified form of relief passage in the pump cylinder.

Referring to Figures 1 to 3 ofthe said drawings, which show a .convenient embodiment ofV the inventionin connection with an appliance for controlling the downward movementl of the pressure,n

or draw ring of a press, the pins I depending f from the said ring (not shownrest-.upon a prese,

sure plate 2 supported upon the upper end of the shank 3 of a main ram or plunger 4 movable-iin 'I a primary cylinder 5 the lower end of which is' connected by a main pipe or conduihccmposed operated pump, indicated at 3l, from which an outlet pipe 32 is connected with the pipe 'I formfingpartr of'ftheipipe line .between the two cylinders 58. By operating the pump iiuid can be chargedinto the system so as to ll the primary *cylinder 5 and the pipes G, l, between the two t cylinders.

of pipe sections 6, '1, to the upper end Yof a -secondary cylinder 8 mounted on the top of a feeder tank 9 adapted to contain a hydraulic fluid'.

An upwardly-opening. one-way valve II) is tted'. in. the said mainv` pipe or: conduit, between thezpipe' sections 6,; 'Ipsa a'szo'nly to allow'i'luidlto pass' freely in. an r upward direction for.- charging the primary cylinder'. 5,1.butithis one-'way'.valveais bypassed? by' a branclr` l passage .I I fffitted: with;l a springeloadedl pressure. controlling .valve 1.2.; forming" the.. subject-matten ofi application? Noi 103,2725gwhich offers aresistance to. thepassage of 'fluidi from? the; primary cylinder 5' to the secondary Vcylinder 8i under. the: 'effect'` of.' downward pressure exerted` u'ponthem'ai'riV ranrlli by tlie draw ring..` L -Y j Y The` secondary cylinder8::is..open at its=lower end-to theY interiorgof:v the feeder tanli:9,l and it contains a control; piston. I 3:- adapted .to be" depressed, by the; uid admitted into` the: cylinder, against the upwardforcerexerted'bya `coiled compression spring -Ialapplied beneatlrthe headof the'piston and supported: at its lower-:end upoma stationary thrustf 'plate'A I 5' suspended `from; the lower* open endof 'thezcylinden lspaced theretoabymeans of long bolts 116-."

The-'said control' piston* vI3 in the. secondary cylinder!!v carries a dependingrxstemadapted to constitute the plunger -II-v of 1aE bala'nc'erfspumpz This .plunger-I1 has`A a central'axialf passage: 214 through it,w this passageopening; at itsxupper' end into? the space above thee controlV piston' I'Hzand terminating at its jlovverend` inva-.valvechamber I8 containing a ball yalvef I9 (Figures 2 andIB.) cos-operating wi-tha-seatingY at the upper end of a passageV ina plug 2l) screwed; intoy theflowei end of1the va1ve chamber. 'I-heballV valvemt can open upwards against` a` spring: 2 I-.tofa'llow fluid to passtothe top `facefoi'the controljpiston but closesonto its seatingto-prevent fluid fromrowingI through the a-Xialpassage 'the 'reverse'idirection., The plunger I1- has aisolid-head-fportion' 22V at. its lower extremity, and..abovefth-is. head portion longitudinal grooves-23.. are. formed vin the sides of the plunger, these grooves extending to positions near the middle of the .length'of the plunger, as shown in Figure l.

The said plunger I'I slides within a stationary pumpl cylinder 25 surrounded by the compression spring |14v and resting at its lower end upon the thrust plate I 5 that supports the said spring. An aperture 26 controlled by an upwardly-opening ball valve- 2'1; is provided in'the thrust plate I5, so that duid can enterr thel cylinder 25 from `the feeder tank 9- but cannot be: discharged from the ylinderthrough the `bottom passage. The cyl.- inder 25. has. two internal diameters, the upper portion of the cylinder havingaizbore 28 exactly corresponding to ythe diameter; of: the pump 11n-:the: operation of the appliance, the feeder tank Sissupplied with fluid up to a suitable level, which' may be determined by a pet cock 33, and this fluid enters the pump cylinder 25 through the-lower end;'the=ball valve12'I- rising Vtoadnrit the fluid. When-'the system-has been 'chargdi bythe handgpump; the appliance isi `rezrtdyto function. WhenA the-mainram-4- is depressed', theiiuid'inthe primary: cylinder 5l1is; displacedand? is forced through Ytheresistancepassage formed by the`l spring-loaded. valveI I,2,` 'intoAv-the upper end of the secondary cylinder 8-,-"ther`eby depressing the piston I @ther-ein again'stthei actionof the spring 14. When thesforceappl'ied to the ram is relieved, thespring MYassertsrit--`v self! and raises the piston I3?i'n` theA secondary cylinder, which thus-1 returns the iiuidl'fautive'fit to lthe-primary cy'linder, -byway= of'theone'- way. valve .Iin the` connecting-:pipa Vitl'i'eretvys causing the'vram 4to be raised.- Y l Any fluid 'that leaks 'past-"the rami 4^ in. the primary cylinder-is transferir-editothefeeder tank 91 through a pipe 342 connecting .'the'top-oi-saidi cylinder'I to'ftheftankrg: and' any: duid-leaking past; the1.piston .I3 in fthe `secondary cylinder drainsdirectlyi into the tank. 1 It isI necessaryvtoisiipr plyA fluid: to the systemfto compensate for'th'at which has leaked past the ram and pistoni-.andg thisfeifectefcl by: the rbalancer pumpcwh'ch :operates so: as automatically to restore toftli'efs-ys-4 tenr a. quantity. that: balances!I the. arrrount-of=v fluid; that hasleaked.. Thus,- during f each down-#- ward" movement of, thefeontrolV piston I3rrin the secondary' cylinder,v the fpump.` v plunger head1/7.2 first' moves; a certain distance 'downwards in .the upper bore portion; 285 .ofthe pumpv cylinder`-25 which is vof smaller diameterxligure.- 2)1,: and during this :initial .movement .'fpumping-:iftalces place duetothef'ud 1in the: cylinder beingrfdisplaced upwardlyI past' the. ballI va-lve'-y Ii9 in plunger stemv and through the axial pas'saigief1211E to the upper face ofi-thecontrol' piston I`3-. 'When however, thelpump' plunger IThas deseendedso' far that the longitudinal# groovesy 23 "above-1'its head 22 ent-er the enlarged lower portion 290i thecylinderbore', as inV Figure-3, pumping ceases', as the' working space of the pump cylinderfis connected to exhaust, Vthefluid displacedffroin the cylinderl 54 i'lowing upwardly,alongthelohr gitudinalA grooves. Zaintorthe feeder tank.- Some off this displacedv Afluid: can .alsoy enter the-tank through the. ports 302m the wall, of rth'e.upp.er portionrof the--pumpcylinden On thecupward: stroke of thefcontrol piston I3f,- uid'cafnf flow into thee-pump :cylinder throughv the@V grooves.: 2s and' ports 30 Iuntil'; thevplungerf head 221 Sagan: moves into; theyA smaller; bore'. 212 -of-l the cylinder (Figure: 2i.' and: thea-filling' of the .purnpf lcylin'' s. der lis thenveompleted by drawing fiuidinton through'th'e bottom ball valve 21."v f f l If the amount of fluid returned to` the'jupper.

face of the control piston I3 is greaterl than the amount lost from the system-by 'leakagefthen the said 'control lvpiston "will: not rise' tothe top ci the secondary 'cylinder 8, land* as the ex'c'essiamount increases, so will the top position reached by the' control pistonbe lowered. This resultsin the effective .pumpingv throwvof the'pump being correspondingly reduced, as'the groovesV 23 .above they pu'mpplunger'head will reach thelarger bore v29 Ofthe'CyIlnder aftera shorter downwardl move-2f ment. Consequently 'the amountof iluid pumpedy back into the 'system will `beV ,prop'o'rtionately're`y duced until a, conditionof balance is reached,

when the amount of. fluid returnedtothe system exactlyvbalanees thefarriount'lost yby leakage. I

".'Rotation'of 'plungerll relatively to cylinder25 may be pre-vented by any'convenient means soas to ymaintain" the groovesfi23: in alignment -withi v3II. For example, Vanother groove sin'rila'rv tof 'groovesl23' may be-provided in the plunger 'and engagedbya pin or peg carried by cylinder '25J fIf Athe-apparatusv should beV left inoperative-for any' lengthy period. the ram 4 in the primary-cylinderf can be allowed` to drop by 'its' Weight and;

fluidfthatfhas :leaked: past it will" collect "'ab'v'e" iti'fIo get ridfof this accumulatedle`aljn'ige' fluid it is 'only necessary 'to' recharge vthe primary /cyl'e inder by operating 'the handy pump? '3 I.; and the said. 4leakage- 'fluidV `will be 'displaced by th'aS- cendingxram )and returned to the-tank '9 by 'means Invthis construction,l the primary lcylinder 5 is fixed by studs 34 to a cover plat'e35lboltedto the bedring 36of the press, `'andthe pressure plate ingtin' the. cylinder 5, said ram b'eing supported ona spring .31.' The secondary" cylinder'isnatffj tached byibolts to the bottom-plate'B-of cylinder 5;? and' is closed at Yits flower en dbyva platellsi,this lower. portion of thev .secondary 'cylinder forming a sump forrcontaining-hydraulic fluid, and a ll'a.

ing orifice' 4,0,"b'eing provided. Fluid;that leaks pastzthe ram 4 Ais returned tothev cylinderfil through apassageor passagefs1-4fl` provided infth'e walls-.of cylinders 5, 8.?1'llhe As'econdarypistonf'I3 in cylinder 8 is"supporte'd' upon" a' 'spring I 4 vresting on'the bottom plate 39,'and a ver/ticalspring"loadQ edvalve v42',` equivalent to-theyalve I2 in jFige ure l, is,supported'verticallyvupo'n'a" spring 413 contained within ahousing 44screw'ed intolsaid bottom plate-'39.v This valve 42 zo-operates with `a seating at the lower end ofva passage k45in` af nipple member4 46 screwed into the centre 'ofV lthe bottom plate 38fof cylinder 5. Whenthe ram 4 descends,r fluidY incylinder 5 is displaced and forced past'the valve 42 into the vspace above the secondary piston '.I3, which I is thusv depressed against the actionk of the spring I4. Wher'ithepiston I 3-y rises, fiuid is returnedfrom cylinder-'8* torcylinder 5; through `'passages l41, controlled hall valves 148, 1 provided in 'the "plate 38. 'I

.Thev balancer pump. comprises valve 42, and having-Lai.headiportion 22 whichl 28 of the pump cylinder. -25 which'is'fcarried by:

. the bottom plate 39,' the lower bore- 2910i: said cylinder being of larger' bore An 'armularispacef 49-is provided around the smallerbore..28',-'f=rom= which pcrts` 30 'lead intofthe cylinder 8'.: *Longiwz tudinalf'igrove's '23 `are @provided in the :periph-'f `f ery of the plunger I1. above' the head '22: vA-

o'f 1 the!` plunger v I'I hand" 'at' points onzfthe. outer: periphery. thereof above the head- 22,r .irrl'iilst'fan-r other passage 52, controlled by-an upwardly-- opening ballvalve 53, connects the endsfacaof:

V4the plungerito the lspace 24. i

The'l operation of the pump is substantial@ ni' same Yasthat' shown ingFigures V1k to `3; .iWhenl Athe space 24 above the pistonl 3. When,"however','`

the'- head `22 .leaves the smaller-diameter2borev 28- andv is 'wholly .within thelarger-diameterifbore- 29, as inligure 6, pumping ceases, as theiworking space' is -connected i to; exahust,"i the fluid :merely flowing? past`r the' plunger: head and 'ff through grooves 23linto thecylinder 8. Onthe upward stroke of piston I3,=fluid can ilow into thepumpj cylinder 4125y through' the l grooves 23 1 andl ports. 30 until the plunger'fhead22 againfmoves into the smaller bore: 28' .ofgithe cylinder Vlr(Figure :5), and the filling of. the pump cylinder.. 'fis'zf then completed Aby .drawing-lfluid vinto: it; throughv passage -5II, the valve 5I being open. l n L-Ifthe amount `of ,fluid 'returned to: theL-upperl facerof t piston; I.3 is; .greater than'fthe ,amount neededV for replenishingA the system, thensythe piston I3vwillnot risesto the' top off'the 'cylinderl 8,-"and a's'the excessamountincreases so' will the top'position of said piston cbe'lowered, resulting'v in a correspondingly reduced elective'throw-cf the pump plui'iger;l 1-,4 1 Irr the modiflcation shown in Figurecl; the', pumpv plunger-is stationary and ,-the' pum'pafcylf; ind'er isimovable. This pump is-'ishowriapplied A to.an apparatus having fseparatefp'rimary ,andl

secondary cylinders' connected by; pipes, as ini Figure `1. The secondary cylinder -81 is attached" 150..;a `:coverfplate Y54 secured to v4the .top of; tank' lso-ias to depend Lthereing Thepump plunger consists of an upstandingtube 55I supportedsupon the1bottom thrust/plate "I5 which is'- connectedl to ,cylinder 8v-byi rods,- tI 6; The' said plunger.;K 55` hasgan/'axial passage ,5,6l .open to the tanlra'txits lower end 'and provided, below thefplunger head 51, with lateral-ports or passages v58; Vwhilst above'. these ports or passages is another passage 259 open to the end ofthe plunger buticontrolled. by an upwardlyopeningball valvev Iithat'wili allow4 fluid to pass upwards into .the .pumpcylin'derV IfI- but which prevents.. returntflow. 'The said tube.depending from the controlpiston I3finrthe' vpassage `5B,V controlled-by a downwardlyeopening: ball valve 5I, is provided 'betweenfthelweriace* 4. A hydraulic pressure-controlling appliance comprising a primary cylinder containing a hydraulic fluid, a pressure-applying ram in said cylinder, a secondary cylinder connected to the primary cylinder through a resistance passage, a piston in said secondary cylinder, a spring in said secondary cylinder opposing movementI of the said piston, a fluid-containing vessel, and a balancer pump for supplying fluid from said vessel to the space above the piston to compensate for leakage, said pump consisting of a plunger carried by the piston in the secondary cylinder, a stationary cylinder in the fluid-containing vessel, a one-way inlet valve for admitting fluid into the pump cylinder from the vessel, and a one-way outlet valve for discharging uid from said pump cylinder into the space above the piston in the secondary cylinder, the pump plunger having a head portion and being provided behind the head portion with an exterior passage leading to the fluid-containing vessel, and the pump cylinder having two internal diameters the smaller of which corresponds to the diameter of the plunger head portion, so that pumping takes place only while the plunger head portion is moving within the smaller diameter of the pump cylinder, the pumping being stopped when the exterior passage of the plunger enters the larger diameter of the pump cylinder.

5. A hydraulic pressure-controlling appliance comprising a primary cylinder containing a hydraulic uid, a pressure-applying ram in said cylinder, a secondary cylinder connected to the primary cylinder through a resistance'passage, a

piston in the secondary cylinder, a spring in said secondary cylinder opposing movement of the piston, a Huid-containing vessel, and a `balancer pump for supplying fluid from said vessel to the space above the piston in the secondary cylinder to compensate for leakage, said pump consisting of a plunger carried by the piston in the secondary cylinder, a stationary cylinder in the fluid-containing Vessel, a one-way inlet valve controlling a passage in the bottom of the pump cylinder, a one-way outlet valve controlling a passage in the plunger for discharging fluid from the pump cylinder into the space above the piston in the secondary cylinder, the pump plunger having ahead portion and being provided above the head portion with a longitudinal exterior passage leading to the fluid-containing vessel, and the pump cylinder having an upper portion of a diameter corresponding to the diameter of the plunger head portion and a lower portion having its Wall recessed to provide a relief passage, so that pump- 10 ing takes place only While the plunger is moving within the upper portion of the pump cylinder, said pumping being stopped when the exterior passage of the plunger moves into the lower portion of the pump cylinder.

6. A hydraulic pressure-controlling appliance comprising a primary cylinder containing a hydraulic fluid, a pressure-applying ram in said cylinder, a secondary cylinder connected to the primary cylinder through a resistance passage, a piston in the secondary cylinder, a spring in said secondary cylinder opposing movement ofthe piston, a fluid-containing vessel, and a balancer pump for supplying fluid from said vessel to the space above the piston in the secondary cylinder to compensate for leakage, said pump consisting of a plunger carried by the piston in the secondary cylinder, a

stationary cylinder in the fluid-containing vessel, a one-way inlet valve controlling a delivery passage in the plunger between the lower end thereof and the side surface, a one-way outlet Valve controlling a passage in the plunger for discharging uid from the pump cylinder into the space above the piston in the secondary cylinder, *the pump plunger having a head portion and a longitudinal exterior passage leading to the fluid-containing vessel, and the pump cylinder having an upper i portion which has a diameter corresponding to the diameter of the plunger head portion and has a recess therein co-operating with the delivery passage in the plunger and communicating with the Huid-containing vessel, and a lower portion the wall of which is recessed to provide a relief passage, so that .pumping takes place only while the plunger is moving within the upper portion of the pump cylinder, said pumping being stopped when the exterior passage of the plunger moves into the lower portion of the pump cylinder.

ARTHUR CARTER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,664,485 Rode Apr. 3,1928 1,897,462 Carter Feb. 14, 1933 2,436,573 Heynes Feb. 24, 1948 FOREIGN PATENTS Number` Country v Date 406,392 Great Britain Mar. 1, 1934 446,279 Great Britain Apr. 27, 1936 

